This invention relates to a stator winding and coil lead termination method and apparatus. The invention is intended primarily for use in the manufacture of 2-pole stators for dynamoelectric machines, such as motors, but may have application to the manufacture of other devices.
The disclosures of the following patents are hereby incorporated by reference herein.
1. U.S. Pat. No. 4,074,418 to Pearsall
2. U.S. Pat. No. 5,186,405 to Beakes et al.
3. U.S. Pat. No. 5,586,384 to Newman
4. U.S. Pat. No. 5,413,403 to Beakes et al.
Many electric motor stators are configured to include a non-conductive terminal board mounted to an end face of the stator core, which terminal board carries electrically conductive terminals to which start and finish leads of the electric field coils wound onto the core are attached. Such stators are particularly suited for fully automated production because the electric field coils may be machine wound onto such stator cores and the start and finish leads of each coil may be at least temporarily secured to the terminal boards or terminals mounted thereon before the wound stator is removed from the winding machine for further processing. The coils will not unwind or despool upon removal of the stator from the winding machine because the finish leads are each secured to the terminal board or a terminal thereon. The start leads and tap leads, as is well known, are each trapped by their respective coil turns and may, in addition, be connected to the terminal board or terminals thereon. Tap wire leads may also be trapped by the coil turns and may be connected to the terminal board or terminals thereon.
This invention is directed to a method and apparatus for manufacturing stators with such terminal boards.
The above listed Pearsall U.S. Pat. No. 4,074,418 shows apparatus for inserting stator coil lead wires into terminal boxes on a stator core while the stator is in the winding station. Pearsall provides wire guide members that are aligned with slots in the terminal boxes and lead pull, cut and hold assemblies which align the stator coil leads with slots in the terminal boxes, and a lead wire insertion assembly movable along the axis of the stator winding ram or spindle. The lead pull, cut and hold assemblies include wire grippers which are limited to movements in horizontal and vertical directions. The insertion assembly has two pairs of wire insertion fingers having notched ends that are moved to positions outside the terminal boxes. When so moved, the notched ends of the insertion fingers engage the coil lead wires and force them into the slots in the terminal boxes. This construction enables the connection of the coil lead wires to the terminal members on the stator and avoids the need to connect the lead wires to temporary winding clamps at the winding station.
Beakes et al. U.S. Pat. No. 5,186,405 shows a turret stator winder including mechanisms useful in the practice of the instant invention. These include a stator winding head 92 with a shuttle or ram 94 and a programmably-operable lead pull assembly 208 that includes wire grippers 84. These also include pairs of winding forms 80 and 82, winding form retainer blades 130 and 132, and mechanisms for moving the winding forms toward and away from a stator located at the winding station. The wire grippers 84 are movable in both vertical and horizontal directions, as are the wire grippers shown in the Pearsall ""418 patent. Moreover, the lead pulls of the Beakes et al. ""405 patent includes mechanism for pivoting the wire grippers 84 toward and away from the plane of the end face of a stator at the winding station.
It is also known in the prior art to utilize wire guides and a lead pull assembly having pivotal wire grippers as shown in the Beakes et al. ""405 patent to place lead wires into the slots of terminal boxes without the use of insertion fingers.
The present invention could be used with a turret stator winder as shown in the Beakes et al. ""405 patent. The invention could also be used in connection with an in-line stator winder in which stators move along tracks to and from the winding station. The Newman U.S. Pat. No. 5,586,384 is incorporated herein to show a representative in-line winder with which this invention could be used.
Turret stator winders and in-line stator winders may include mechanisms to automatically place stators at a winding station. This invention is also usable with stator winding machines which do not have associated stator handling mechanisms and in which stators to be wound are manually placed in a suitable clamp in the winding machine.
Both the Beakes et al. ""405 patent and the Newman ""384 patent show winding machines that include a winding station at which the coil lead wires are connected to temporary wire clamps which are separate from the stator being wound. The stators and the temporary clamps are moved with the stator to a robotic lead connect station at which the lead wires are removed from the temporary clamps and at least temporarily connected to the terminal members on the stator.
Beakes et al. U.S. Pat. No. 5,413,403 shows a lead pull assembly or wire gripper having upper and lower clamping jaws 36 and 26, respectively, and a fitting having a sharpened edge for severing a gripped wire segment.
Recent developments in stator technology have resulted in demands for stator winding methods which cannot be met by known stator winding machines. In particular, each coil of a conventional 2-pole stator has a running winding pattern that includes two coils wound about separate pole pieces from two separate strands of wire. Each coil has a start wire and a finish wire connected to separate terminal members and both coils are usually wound at the same time from two different strands of wire. A recent requirement is for stators in which both running coils are wound from a single strand of wire, with a first coil wound in one direction on one pole piece and a second coil wound in the opposite direction on the other pole piece. Such a winding pattern reduces the number of start and finish wire terminals from four to two. This can result in a substantial savings in manufacturing cost because of the reduction in the number of terminal connections that must be dealt with. There are no prior machines known that are capable of winding and terminating such stators entirely automatically. Also, some stators have wire guide posts about which parts of stator coil lead wires must be looped because of certain winding pattern characteristics. Robotics machines capable of looping coil lead wires about such posts are known, but such machines require a lead wire connecting station which is separate from the winding station.
The following terms, in both plural and singular forms, used in the specification and claims are used in the senses indicated below, unless a different meaning is clear from the context in which the terms are used.
xe2x80x9cActuatorxe2x80x9dxcfx80refers to actuators comprising a cylinder, a piston and a piston rod, which are usually air operated but could be hydraulically operated.
xe2x80x9cLead pullxe2x80x9d is used as a shortened expression for lead pull, cut and hold. Thus, a xe2x80x9clead pull assemblyxe2x80x9d as used herein denotes a lead pull, cut and hold assembly. The term xe2x80x9clead pullsxe2x80x9d also denotes a lead pull, cut and hold assembly.
The terms xe2x80x9cupper,xe2x80x9d xe2x80x9clower,xe2x80x9d xe2x80x9cverticalxe2x80x9d and xe2x80x9chorizontalxe2x80x9d are used in a relative sense and not in an absolute sense. The term xe2x80x9cfrontxe2x80x9d in reference to the winding machine or the stator is used to refer to the parts of the machine and stator facing an observer standing in front of the winding shuttle during a winding operation. Accordingly, the term xe2x80x9crearxe2x80x9d is used in the opposite sense. Thus, for example, at the outset of a winding operation, the winding shuttle moves from behind the rear end of the stator to the front end of the stator to extend the start wire through the bore of the stator.
A xe2x80x9cstart wirexe2x80x9d is the segment of a magnet wire extending from a lead pull gripper through the bore of the stator to form the first side of a stator coil. The wire segments that extend across the front and rear of a stator pole piece are referred to as the xe2x80x9cend turns.xe2x80x9d Because the first end turn merges with and extends from the start wire, the transitional wire segment at the front end of the start wire and the beginning of the first end turn are indistinguishable and is considered to be part of the start wire or part of the first end turn. Some stators, as will be further discussed below, have posts around which start or finish wires are looped. During the winding and lead termination process, these stators typically have wire segments which extend from a wire gripper around the forward end of a pole piece in a direction opposite to the direction in which the coil is to be wound. Any wire segment between a wire gripper and a coil that extends at the beginning of a winding sequence in a direction around a pole piece which is opposite to the direction in which the coil is wound is considered to be part of the start wire.
A xe2x80x9cfinish wirexe2x80x9d is the segment of a magnet wire extending from the last turn of a stator coil to a wire gripper. Because the last end turn merges with and extends to the finish wire, the transitional wire segment at the ending of the last end turn to the finish wire is indistinguishable from the finish wire and is considered to be part of the finish wire or part of the last end turn. Any wire segment that extends at the end of a winding sequence from a coil to a wire gripper that extends in a direction around a pole piece which is opposite to the direction in which the coil was wound is considered to be part of the finish wire.
xe2x80x9cLead wirexe2x80x9d is either a start wire or a finish wire.
xe2x80x9cTerminal memberxe2x80x9d is used to refer to either conductive terminals or to terminal support members, which are typically non-conductive, such as terminal sockets.
An object of this invention is to provide an improved stator winding and lead terminating method and apparatus which is capable of automatically winding 2-pole stators having two pole pieces with coils of wire wound from a single strand of wire about both pole pieces.
Another object of this invention is to provide a method and apparatus for trapping cross-over wire segments between stator coils wound from a single strand of wire on two pole pieces of a stator so that the cross-over wire segments are trapped against an inside wall of the stator.
Another object of this invention is to provide an improved stator coil lead terminating method and apparatus which is capable of complex manipulations of stator coil lead wires at a winding station.
Still another object of this invention is to provide a method and apparatus for automatically looping stator coil lead wires about wire guide posts on a stator core in the course of forming coil lead terminations.
Another object of this invention is to provide an improved stator lead pull method and apparatus.
Another object of this invention is to provide an improved rotary to reciprocating and oscillating motion transmitting method and apparatus for a stator winding machine.
Other objects and advantages will become apparent from the following description and the drawings.